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T. S. HAMILTON.

LUBRICATING STRIP FOR LEAF SPRINGS.

. APPLICATION FILED 050.3. 1919.

Reissued June 1, 1920. 1 4,870.

Gamma;

uurrso srArE's PATENT OFFICE.

TKO! 8. MILTON, OI KANSAS CITY, KISSbUBL ASSIGNOB OF ONE -HALF 'IO WILLIAM E. MERRILL, OI KANSAS CITY, MISSOURI.

LUBRIGA TING-STRIP FOB LEAF-SPRINGS.

Specification of Reissued Letters Patent. Reigsued Jun 1, 1920.

on mn No. 1,328,856, dated December 2, 1919, Serial No. 320,683, filed August 28, 1919. Application for reissue filed December 8, 1919. Serial No. 342,238.

To all whom it may concern Be it known that I, THOMAS S. HaM L'roN, a citizen of the United States, resldlng at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Lubricating- Strips forLeaf-Springs, of WhlCh the f0 lowing is a specification.

This invention relates to new and useful improvements in a lubricating strip for leaf springs and method of producing the same.

Heretofore lubrication of leaf springs has generally been accomplished by separating the leaves of the spring and placlng 01l b6- tween the same with an oil can or the like. An effort has been. made to produce a lubricating strip which may be placed between the leaves of the spring afl'ording a cont1nuous oil suppl therefor but all of these strips with which am familiar have been formed of compressible material soaked with a lubricating agent. The feature of compressibility is an undesirable one 1n that the compressibility of the strip allows play in the spring and causes it to become loose and break. .Also when this carrier strlp has been subjected to continuous action for some time, it becomes so compressed that 1t slips out between the leaves of the spring.

The use of a ready flowing lubricant in such a carrier is highly undesirable in that the action of the spring squeezes the oil from the carrier and it collects upon the edges of the spring and dirt and dust from the road properties of the lubricant in the strip. raphite has been placed upon the face of these compressible strips but in the presence of oil,

graphitehas a tendency to become a gummy mass, which due to 1ts adhesive propertles has a tendency to retard rather than promote free movement of the spring.

Also in the majority of cases where such a strip is used in order hold the strip in place it is necessary that 1t must be continuous throughout the leaf of the spring and the springl therefore must be taken apart 1nsert t e strip.

These objections I have overcome by forming a very thin strip provided upon one slde with an adhesive to secure it to the sprmg.

adhere thereto. Thenin cleaning the spring A binder V1Z' Sheuac Slhcate to remove the grease it is necessary to use 'gasolene and this use of gasolene has a tendency to destroy the lubr1cat1n(g composition extremely hard in texture yet having a high coeflicient of lubrication.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification, and in which like numerals parts throughout the same:

Figure 1 is a side elevation of a spring embodying my invention;

Flg. 2 is an enlarged transverse section therethrough Fig. 3 is an enlarged section through the lubricating strip;

Fig. 4 is a sectional view construction used where the plied to both the upper and of the spring, and,

Fig. 5 is a longitudinal section of the doubled strip.

illustrating the strips. are apunder surfaces Referring" now more particularly to the the numeral 10 indicates the spring and the numeral 11 the strip placed ntermediate these of soda,- varnish, glue or the like 1 qt.

A dry lubricant, via-fine powdered graphite, mica or soapstone 11b.

Powdered alum 1oz.

The paste isapplied to the surface of the baked.

are employed to designate like and then baked in an oven/ pends entirely upon the length of time it is .This fabric is then cut into strips of the size desired for the spring to which it is to be applied and an adhesive applied to' terminating short of the center of the spring.

The gunnn'ed side of the strip adheres to the face of the leaf against which it is placed and prevents shifting of the strip,

while the side bearing the composition provides a smooth dry lubricating surface for the shifting of the spring. In some cases it may be desirable to place two strips between each leaf with the faces bearing the lubricant together so that the friction lies between the surfaces of the strips and not between the strip and the spring.

Under some conditions, I find it advantageous to use a double lubricating strip between each pair of spring leaves, and such a strip is shown in Fig. 5 of the drawings. When such a strip is to be used, two single strips are prepared, as described above, and one is placed on top of the other with the layers of graphite 14: disposed on one another. The two layers of adhesive 15 are then secured to the adjacent faces of the leaves of the spring. The gummed sides of the strips adhere to the faces of the leaves to prevent shifting of the strip, while the sides. bearing the composition provide smooth dry lubricating surfaces for' the shifting of the adjacent leaves of the spring. As shown, the lubricating strips terminate short of the center of the spring. In an ordinary spring construction, and in spring construction shown in the prior art wherein lubricating strips are provided, the leaves of the spring, or the spring leaves, and the lulubricating strips are-tightly compressed by the U-shaped bolts, or other fastening means employed to fasten this spring to the axle of the vehicle. The result is that relative movement of the leaves of the spring is prevented, and the entire spring moves as a unit and shocks and jars are transmitted to the body of the veh1cle.

In the presentinvention, the lubricating strips 11 terminate short of the center of the spring, as shown in Fig. 1 of the drawings, which tends to space the leaves of the spring in the center a slight distance from each other, permitting relative movement of the leaves of the spring and producing a very efficient shock absorber. Shocks and jars are completely taken up in the spring structure and not transmitted to the vehicle body. This 'result is obtained due to the increased flexibility of the leaves of the spring, and the arrangement whereby the individual leaves are permitted .to move" relatively to each other.

Having thus described vmy'invention, I claim:

1. A. lubricating strip for leaf 5 rings comprising a strip of fabric provide upon one side thereof with an adhesive and upon the other side ,with a layer oflubricant.

-2. A lubricating strip forv leaf -s ringscomprising a strip of fabric provide upon one side thereof with an adhesive and upon the other side with a la er of dry lubricant. A lubricating strip for. leaf springs comprising a strip of fabric provided upon one side thereof with an adhesive and upon the other side with a layer of hard lubricant.

4. A lubricating strip for leaf springs comprising a strip of fabric provided upon one side thereof with an adhesive and upon the other side with a layer of lubricant comprising shellac, graphite and alum.

5. A lubricating strip for leaf springs comprising a strip of fabric provided upon one side thereof with an adhesive and upon the other side with a layer of hard lubricant comprising shellac, a dry lubricant and alum and .a filler applied to the outer face of said layer of lubricant.

6. A lubricating stripv for leaf springs comprisinga strip of fabric provided upon one side thereof with an adhesive and upon the other side with a'layer of hard lubricant comprising a dry lubricant and a watery binder adapted to hardenunder the action of heat and pressure.

7. A lubricating strip for leaf springs comprising a strip of fabric provided upon one side thereof with an adhesive and upon the other side with a layer of hard lubricant comprising graphite and a. watery binder adapted to harden under the action of heat and pressure and a filler applied to the outer face of said layer of lubricant.

8. The herein-described method of producing a'lubricating strip for leaf springs consisting in supplying a supporting strip, applying to one face thereof a watery binder containing a dry lubricant, placing the strip under pressure and subsequently baking the strip.

9. The herein-described method of producing a lubricating strip for leaf springs consisting in supplying a supporting strip, applying to one face thereof a paste formed by combining shellac, a dry lubricant and alum, placing the strip under pressure, baking the strip and applying to the opposite face of the strip an adhesive.

10. The herein described method of producing a lubricating strip for leaf springs consisting in supplying a supporting strip, applying to one face thereof a paste formed by combining a watery binder with a powdered dry lubricant and a small percentage of alum, sprinkling upon the surface of the paste flake graphite, placing the strip under pressure, baking the strip and applying .to the op osite face thereof an adhesive.

11. lubricating strip for leaf springs comprising a supporting strip provided on one side thereof with an adhesive and uponthe other side with a layer of lubricant.

12. A lubricating strip for leaf springs comprising a supporting strip provided on one side thereof with an adhesive and upon the other side with a layer of dry lubricant.

13. A lubricating strip for leaf springs comprising a supporting strip provided on one side thereof with an adhesive and upon the other side with a layer of lubricant comprising shellac, graphite, and alum.

14. A lubricating strip for leaf springs comprising a strip of material provided on one side with a layer of lubricant and means on the'opposite side for securingit to one of the leaves of, the spring.

15. An elliptical spring construction comprising a plurality of spring leaves, a lubricating strip arranged between each pair of leaves, and means for securing said-strips to the face of one of said leaves, said strips terminating at a point removed from the center of the spring, whereby the-leaves of the springv are slightly spaced from each other at the center- 16. In combination with an elliptical spring comprisinga plurality of leaves, lu-

bricating means comprising a plurality of lubricatingv strips arranged between the leaves at each end, said strips being provided with lubrication on one side and means on the opposite side for securing said stripsto the leaves, said strips terminating at a point removed fromithe center of the spring.

17 .1A lubricating strip for leaf springs comprising a strip of material provided on one side with an anti-friction surface and means on the opposite side for securing it to one of the leaves of the spring.

In testimony. whereof I hereunto aflix my signature. J

THOMAS s. HAMILTON. 

